driver-core: add include guard to linux/container.h

Add a header include guard just in case.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20190819071606.10965-1-yamada.masahiro@socionext.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>